In the past, carbon materials such as graphite, carbon nanotube, carbon fiber and carbon particles have been widely used as a reinforcing agent or a filler for resin. Also, lamina graphite with a smaller number of graphene layers, which is prepared by the exfoliation of graphite, has been recently attracting attention.
As a composite material of carbon materials and resin described above, a composite material, prepared by dispersing a carbon material such as carbon fiber in an epoxy resin is known as described in the following Patent Literature 1.